Cummins’ Q-series diesels will meet federal Tier 4-Final and Euro IV limits in 2014 with exhaust aftertreatment systems. The QSL9, with up to 400 horsepower, gets a Cummins Compact Catalyst and selective catalytic reduction, for almost emissions-free exhaust. This CCC-SCR system, in scalable sizes, also goes on QSB3.3, 4.5 and 6.7 models, rated at 75 to 400 horsepower. The QSX15 and 11.9 engines will use SCR and a diesel particulate filter. The 15’s top rating is 675 horsepower, 75 more than the Tier 4-Interim model, and the 11.9 goes to 525 horsepower. Tanks for SCR’s diesel exhaust fluid will vary in size by OEM.